<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>动态背景登录组件</title>
</head>
<style>
	* {
	    margin: 0;
	    padding: 0;
	}
	
	body {
	    height: 100vh;
	    display: flex;
	    justify-content: center;
	    align-items: center;
	    background: linear-gradient(200deg, #e3c5eb, #a9c1ed);
	    overflow: hidden;
	}
	
	.container {
	    position: relative;
	    z-index: 1;
	    background-color: #fff;
	    border-radius: 15px;
	    display: flex;
	    flex-direction: column;
	    align-items: center;
	    width: 350px;
	    height: 500px;
	    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
	}
	
	.container .tit {
	    font-size: 26px;
	    margin: 65px auto 70px auto;
	}
	
	.container input {
	    width: 280px;
	    height: 30px;
	    text-indent: 8px;
	    border: none;
	    border-bottom: 1px solid #ddd;
	    outline: none;
	    margin: 12px auto;
	}
	
	.container button {
	    width: 280px;
	    height: 40px;
	    margin: 35px auto 40px auto;
	    border: none;
	    background: linear-gradient(-200deg, #fac0e7, #aac2ee);
	    color: #fff;
	    font-weight: bold;
	    letter-spacing: 8px;
	    border-radius: 10px;
	    cursor: pointer;
	    transition: 0.5s;
	}
	
	.container button:hover {
	    background: linear-gradient(-200deg, #aac2ee, #fac0e7);
	    background-position-x: -280px;
	}
	
	.container span {
	    font-size: 14px;
	}
	
	.container a {
	    color: plum;
	    text-decoration: none;
	}
	
	ul li {
	    position: absolute;
	    border: 1px solid #fff;
	    background-color: #fff;
	    width: 30px;
	    height: 30px;
	    list-style: none;
	    opacity: 0;
	}
	
	.square li {
	    top: 40vh;
	    left: 60vw;
	    animation: square 10s linear infinite;
	}
	
	.square li:nth-child(2) {
	    top: 80vh;
	    left: 10vw;
	    animation-delay: 2s;
	}
	
	.square li:nth-child(3) {
	    top: 80vh;
	    left: 85vw;
	    animation-delay: 4s;
	}
	
	.square li:nth-child(4) {
	    top: 10vh;
	    left: 70vw;
	    animation-delay: 6s;
	}
	
	.square li:nth-child(5) {
	    top: 10vh;
	    left: 10vw;
	    animation-delay: 8s;
	}
	
	.circle li {
	    bottom: 0;
	    left: 15vw;
	    animation: circle 10s linear infinite;
	}
	
	.circle li:nth-child(2) {
	    left: 35vw;
	    animation-delay: 2s;
	}
	
	.circle li:nth-child(3) {
	    left: 55vw;
	    animation-delay: 6s;
	}
	
	.circle li:nth-child(4) {
	    left: 75vw;
	    animation-delay: 4s;
	}
	
	.circle li:nth-child(5) {
	    left: 90vw;
	    animation-delay: 8s;
	}
	
	@keyframes square {
	    0% {
	        transform: scale(0) rotateY(0deg);
	        opacity: 1;
	    }
	
	    100% {
	        transform: scale(5) rotateY(1000deg);
	        opacity: 0;
	    }
	}
	
	@keyframes circle {
	    0% {
	        transform: scale(0) rotateY(0deg);
	        opacity: 1;
	        bottom: 0;
	        border-radius: 0;
	    }
	
	    100% {
	        transform: scale(5) rotateY(1000deg);
	        opacity: 0;
	        bottom: 90vh;
	        border-radius: 50%;
	    }
	}
</style>
<body>
    <div class="container">
        <div class="tit">登录</div>
        <input type="text" placeholder="账号">
        <input type="password" placeholder="密码">
        <button>登录</button>
        <span>没有账号？<a href="#">去注册</a></span>
    </div>
    <div class="square">
        <ul>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
        </ul>
    </div>
    <div class="circle">
        <ul>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
        </ul>
    </div>
</body>

</html>